Nocturnal Wakefulness Is Associated With Next-Day Suicidal Ideation in Major Depressive Disorder and Bipolar Disorder

Abstract

Objective: Self-reported sleep disturbances may confer elevated risk for suicidal ideation, suicide attempts, and death. However, limited research has evaluated polysomnographically determined sleep disturbance as an acute physiologic risk factor for suicidal thoughts. This study sought to investigate the relationship between nocturnal wakefulness in association with next-day suicidal ideation using overnight polysomnography assessment from data collected between 2006 and 2013.

Methods: Sixty-five participants with DSM-IV-diagnosed major depressive disorder or bipolar depression underwent overnight polysomnography monitoring in a sleep laboratory. The Hamilton Depression Rating Scale (HDRS) was administered the morning after polysomnography recording to assess next-day suicidal ideation, severity of depressive symptoms, and subjective sleep disturbances.

Results: Using a generalized linear mixed model, a significant time-by-ideation interaction was found indicating greater nocturnal wakefulness at 4:00 am among participants with suicidal ideation (F4,136 = 3.65, P = .007). Increased time awake during the 4:00 am hour (4:00 to 4:59) was significantly associated with elevated suicidal thoughts the next day (standardized β = 0.31, P = .008). This relationship persisted after controlling for age, gender, diagnosis, and severity of depressive symptoms.

Conclusions: Greater nocturnal wakefulness, particularly in the early morning hours, was significantly associated with next-day suicidal thoughts. Polysomnographically documented sleep disruption at specific times of night may represent an acute risk factor of suicidal ideation that warrants additional research.

Trial registration: ClinicalTrials.gov identifier: NCT00024635.

Conflict of interest statement

Declaration of Interest: Dr. Zarate is listed as a co-inventor on a patent for the use of ketamine and its metabolites in major depression. Dr. Zarate has assigned his rights in the patent to the US government but will share a percentage of any royalties that may be received by the government. The NIMH has filed a use patent for the use of scopolamine in the treatment of depression, and Dr. Furey is identified as a co-inventor on this pending patent application in the US and an existing patent in Europe. This work was completed while Dr. Furey was a staff scientist at the National Institute of Mental Health; she is now a full-time employee at Janssen Pharmaceuticals, Neuroscience Research and Development, La Jolla, CA. All other authors have no conflict of interest to report, financial or otherwise.

© Copyright 2016 Physicians Postgraduate Press, Inc.

Figures

Figure 1

Polysomnography (PSG) documented minutes awake per hour. Each line represents the sleep of one participant. Figure 1A depicts the sleep of participants who reported no suicidal ideation the next day. Figure 1B depicts participants who reported suicidal ideation the next day. Time periods represent the entire hour of wakefulness (i.e. midnight is equivalent to 00:00 to 00:59).

Figure 1

Polysomnography (PSG) documented minutes awake per hour. Each line represents the sleep of one participant. Figure 1A depicts the sleep of participants who reported no suicidal ideation the next day. Figure 1B depicts participants who reported suicidal ideation the next day. Time periods represent the entire hour of wakefulness (i.e. midnight is equivalent to 00:00 to 00:59).

Figure 2

Average time awake from midnight to 4:00 AM, by ideation or no ideation the next day. *p